Even at a 100 person company I knew, half the organization used gchat and half used jabber/webex connect. Each side had champions that spent a ridiculous amount of time trying to convert everyone to one platform, and last I checked they still hadn't succeeded.
There are gui clients that support both protocols (i.e. I think Pidgin does) - why not just write a plugin that allows to cross-communicate between the two?
As time goes on I get more and more disillusioned with solutions that begin with "why not just write".
Nothing excites me more than having to think about supporting yet another codebase deployed to non-technical people who will undoubtedly cause more bugs than thought possible and open more JIRA tickets about it with increasingly vague title names.
At some point Slack or [integration of choice] is cheaper than having an internal engineering team to write half-baked communication solutions.
